Women elect to use reversible contraception to prevent unintended pregnancies, while preserving their future fertility. Some women may opt to delay childbearing to achieve educational, professional, financial or societal goals. Women who had used contraception to delay pregnancy may have the belief that the former contraception method was the reason for their inability to conceive after discontinuation of use. In fact, both parity and age affect fertility in women regardless of their use of contraception.
The cumulative effects of endocrinological, medical, surgical and gynecological problems increase with age and may significantly decrease the fertility potential, regardless of contraceptive use. Such problems may include diabetes, thyroid disease, polycystic ovary syndrome, obesity and exposure to sexually transmitted diseases.
Both the estrogen and progestin components of the combination hormone methods contribute to their mechanism of contraceptive action. The estrogen component suppresses FSH hormone and prevents development of a dominant follicle. The progestin component prevents ovulation and also thickens the cervical mucus.
Birth Control Pills (BCP):
Although there is no impairment of fertility following BCP use, there may be delayed return to fertility, which means that it may take longer time to conceive compared to a woman without a history of BCP use. Eventually, the fertility rates become similar, with 90% of BCP users becoming pregnant within 24 months.
Transdermal Contraceptive Patch:
Although there are no long term studies with the patch, the effects are expected to be similar. Gonadotropin levels return back to baseline levels by six weeks after discontinuation, similar to BCP, suggesting that return to fertility is also rapid.
No long term studies are yet available to assess the return to fertility after discontinuation of the vaginal ring, but is expected to be similar to BCP. The mean time to ovulation after removal of the ring was 2-3 weeks.
Depo-Provera inhibits LH, thus prevents ovulation without changing the secretion of FSH. The clearance of progestin from serum takes a long time (average of 160 days). Mean time to ovulation is also delayed (mean of 210 days). For these reasons, Depo-Provera has a prolonged contraceptive effect. The average time to conception after discontinuation of the drug has been reported to be 10 months. Despite the delay in fertility, cumulative pregnancy rates have been found to be similar with other contraceptive methods.
Intrauterine Device (IUD):
There are currently two IUDs available for use in the US: Copper-containing IUD (ParaGard®) and the progesterone containing IUD (Mirena®). Both IUDs create an inflammatory reaction in the endometrium that results in a spermicidal intrauterine environment and provide contraceptive effect. Mirena also thickens the cervical mucus by the progesterone effect and inhibits sperm transport. Studies have found no impairment of fertility after removal of either of the IUDs.
Progestin hormone within the implant/rods provides contraceptive effects by inhibiting ovulation, thickening cervical mucus and by changing the endometrial maturation. The hormone levels are undetectable in the serum one week following the removal of the implant. The use of the implant does not impair fertility and resumption of ovulation occurs rapidly following its discontinuation.
With the exception of Depo-Provera, return to fertility is very rapid after discontinuation of the reversible contraceptive methods. Women who desire pregnancy within a relatively short period of time after stopping contraception should consider alternatives to using Depo-Provera. There is no increased risk of primary or secondary infertility with any of these methods, but patients should be counseled on the expected time frame of the return to fertility with different types of contraceptive methods to suit the individual childbearing goals. Preservation of future fertility may in fact be enhanced with the use of combination hormonal methods, through the protection against upper genital tract infections such as pelvic inflammatory disease (PID) and ectopic pregnancy.